JPH11172085A - Production of polyethylene terephthalate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyethylene terephthalate resin with an improved rate of crystallization by rendering the crystallization temperature lowered without reducing clarity. SOLUTION: At the time of filling particulates of a polyethylene terephthalate resin into a transport container, in the transport container after filling the particulates therein or at the time of discharging them from the transport container, the particulates are brought into contact with a member composed of a crystalline thermoplastic resin of a different type therefrom to incorporate trace amounts of the crystalline thermoplastic resin thereinto and subsequently, melt kneaded and formed into a polyethylene terephthalate resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a polyethylene terephthalate resin composition, and more particularly, to a method for lowering the crystallization temperature without lowering the transparency, especially for bottles for food packaging and the like. The present invention relates to a method for producing a polyethylene terephthalate resin composition useful for molding.

[0002]

2. Description of the Related Art Conventionally, as bottle containers for carbonated drinks, fruit juice drinks, alcoholic drinks, drinks such as tea and mineral water, liquid seasonings, edible oils, liquid detergents, cosmetics, and the like.
Polyethylene terephthalate resins have attracted attention in terms of excellent transparency, gas barrier properties, safety and health, and the like in addition to excellent mechanical properties and chemical properties, and have shown remarkable growth.

[0003] These polyethylene terephthalate resin bottle containers are usually formed by stretch-blow-molding an injection-molded preform in a blow mold. However, contents such as fruit juice drinks that require hot filling are used. In the case of a container, in order to increase the heat resistance of the bottle, the preform or the plug portion of the bottle is heat-treated and crystallized. In order to increase the density of the body, the temperature of the blow mold is set to 120 to 180.
It has been practiced to set the temperature as high as about ° C. to promote crystallization of the body. However, since polyethylene terephthalate resin has a low crystallization rate, there is a problem that these treatments at the time of bottle molding require time, and improvement thereof has been strongly demanded conventionally.

[0004]

SUMMARY OF THE INVENTION In view of the above situation, the present invention provides a method for producing a polyethylene terephthalate resin composition having an improved crystallization rate by lowering the crystallization temperature without lowering the transparency. The purpose is to provide.

[0005]

Means for Solving the Problems The present invention has been made to achieve the above-mentioned object. That is, the present invention provides a method for filling polyethylene terephthalate resin particles into a shipping container at the time of filling. In the shipping container, or at the time of discharge from the shipping container, the resin is contacted with a member made of a crystalline thermoplastic resin different from the resin to contain a small amount of the crystalline thermoplastic resin, and then melt-kneaded. The gist of the present invention is a method for producing a polyethylene terephthalate resin composition to be a polyethylene terephthalate resin composition.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the polyethylene terephthalate resin includes a dicarboxylic acid unit mainly composed of terephthalic acid or its alkyl (about 1 to 4 carbon atoms) ester and a glycol unit mainly composed of ethylene glycol. The oxyethylene oxyterephthaloyl unit preferably accounts for at least 80 equivalent% of all the constituent units. Further, the content of diethylene glycol units is 1 to 4 mol% based on all glycol units.
Is preferably within the range.

The dicarboxylic acid units other than terephthalic acid and its alkyl ester include, for example, phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid,
Aromatic dicarboxylic acids such as 4'-diphenyl ether dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, and malonic acid , Succinic acid, adipic acid, azelaic acid, aliphatic dicarboxylic acids such as sebacic acid, and as a glycol unit other than ethylene glycol, for example, propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, Aliphatic glycols such as decamethylene glycol, neopentyl glycol and diethylene glycol, 1,1-cyclohexane dimethylol,
Alicyclic glycols such as 4-cyclohexane dimethylol, 4,4'-dihydroxybiphenyl, 2,2-bis (4'-hydroxyphenyl) propane, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane ,
Bis (4-hydroxyphenyl) sulfone, bis (4-
aromatic glycols such as (β-hydroxyethoxyphenyl) sulfonic acid, and further one or more kinds of, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid; Used as a copolymer component.

The raw materials containing these dicarboxylic acid units containing terephthalic acid or its alkyl ester as a main component, and glycol units containing ethylene glycol as a main component,
According to a conventional method, an esterification reaction or a transesterification reaction is carried out at a temperature of about 240 to 280 ° C. and a pressure of about 1 to 3 kg / cm ^{2 in} the presence of an esterification catalyst or a transesterification catalyst such as a metal compound such as manganese. After being converted to bis (β-hydroxyethyl) terephthalate and / or an oligomer thereof, the reaction is carried out in the presence of a polycondensation catalyst such as a metal compound such as germanium and a stabilizer such as a phosphorous compound such as phosphoric acid.
Melt polycondensation is performed at a temperature of about 00 ° C. and a pressure of about 500 to 0.1 mmHg to form a polymer, which is drawn out in a strand shape from a draw-out port provided at the bottom of the melt polymerization tank, and then cut by a cutter. Into a chip, pellet, or spherical particle, and the granular polymer obtained by melt polycondensation is usually 120 to 20 particles.
After pre-crystallization by heating at a temperature of about 0 ° C. for 1 minute or more, 190 to 230 ° C. under a flow of an inert gas such as nitrogen.
Solid-state polymerization is performed at a temperature of about 1 kg / cm ² to a pressure of about ¹⁰ mmHg for 1 to 50 hours to obtain a granular polyethylene terephthalate resin.

[0009] In the present invention, the polyethylene terephthalate resin particles may be brought into contact with a granular material of the polyethylene terephthalate resin at the time of filling into the shipping container, inside the shipping container after filling, or at the time of discharging from the shipping container. Are typically different types of crystalline thermoplastic resins, typically, polyolefin-based resins,
Polyamide-based resins and the like can be mentioned.

As the polyolefin resin, for example, ethylene, propylene, butene-1, etc.
About 8 α-olefin homopolymers, those α-olefins, and ethylene, propylene, butene-1,3-
Other α-olefins having about 2 to 20 carbon atoms such as methylbutene-1, pentene-1, 4-methylpentene-1, hexene-1, octene-1, decene-1 and the like, vinyl acetate, vinyl chloride, acrylic acid , Methacrylic acid, acrylic acid ester, methacrylic acid ester, copolymers with vinyl compounds such as styrene, and the like. Specifically, for example, low-, medium-, and high-density polyethylene (branched or linear) Ethylene homopolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-4-
Methylpentene-1 copolymer, ethylene-hexene-1
Ethylene resins such as copolymer, ethylene-octene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate copolymer Propylene resins such as propylene homopolymer, propylene-ethylene copolymer, propylene-ethylene-butene-1 copolymer, and butene-1 homopolymer, butene-1-ethylene copolymer, butene-1 Butene-1 resin such as propylene copolymer;

Examples of the polyamide resin include lactam polymers such as butyrolactam, δ-valerolactam, ε-caprolactam, enantholactam, ω-laurolactam, 6-aminocaproic acid, 11-aminoundecanoic acid, and the like. Polymers of aminocarboxylic acids such as 12-aminododecanoic acid, hexamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, undecamethylenediamine, 2,2,4- or 2,4,4-trimethylhexa Aliphatic diamines such as aliphatic diamines such as methylene diamine, 1,3- or 1,4-bis (aminomethyl) cyclohexane and bis (p-aminocyclohexylmethane), and aromatic compounds such as m- or p-xylylenediamine Diamine units such as aromatic diamines, glutaric acid and adipine , Suberic acid, polycondensates of aliphatic dicarboxylic acids such as sebacic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, terephthalic acid, and dicarboxylic acid units and aromatic dicarboxylic acids such as isophthalic acid,
And copolymers thereof. Specific examples thereof include nylon 4, nylon 6, nylon 7, nylon 8, nylon 9, nylon 11, nylon 12, nylon 66, nylon 69, nylon 610, and nylon 61.
1, nylon 612, nylon 6T, nylon 6I, nylon MXD6, nylon 6/66, nylon 6/61
0, nylon 6/12, nylon 6 / 6T, nylon 6
I / 6T and the like.

In the present invention, the polyethylene terephthalate resin granules are filled in a transport container, in the transport container after filling, or when the granular material is discharged from the transport container.
A polyethylene terephthalate resin composition is produced by bringing into contact with a member made of the crystalline thermoplastic resin to contain a small amount of the crystalline thermoplastic resin and then melt-kneading the mixture.

As the members and the contact method at this time, it is preferable that particles of the polyethylene terephthalate resin are brought into collision with the members in a space where the members made of the crystalline thermoplastic resin are present. For example, a method of filling a part of a pipe for filling a transport container of polyethylene terephthalate resin particles such as a container or a container car with a crystalline thermoplastic resin, or by lining a crystalline thermoplastic resin or the like. Alternatively, there may be mentioned a method of filling, discharging, and transporting by filling or discharging a filling port, a discharging port, and a container body of a shipping container with a crystalline thermoplastic resin, or by coating a crystalline thermoplastic resin. The contact time of the polyethylene terephthalate resin particles with the member is usually 0.01 to 1 in the case of the above-mentioned filling and discharging.
Although it is a very short time of about 2 seconds, the polyethylene terephthalate resin is used because of a sudden collision contact with the member, and in the case of the above-mentioned container during transportation, not a sudden collision contact but a long time. Can contain a small amount of a crystalline thermoplastic resin. Thereafter, the mixture is melt-kneaded by a conventional method to obtain a polyethylene terephthalate resin composition.

In the present invention, the content of the crystalline thermoplastic resin in the polyethylene terephthalate resin composition is preferably from 0.1 to 100 ppb, preferably 1 to 100 ppb, based on the total amount of the polyethylene terephthalate resin.
Particularly preferred is ５０50 ppb. If the content ratio is less than the above range, the effect of lowering the temperature of crystallization as the resin composition becomes insufficient, and if it exceeds the above range, the transparency of the resin composition tends to be impaired. The intrinsic viscosity of the polyethylene terephthalate resin composition is 30 ° C. in a mixed solvent of phenol / tetrachloroethane (weight ratio: 1/1).
Is preferably 0.6 to 1.0 dl / g.

The polyethylene terephthalate resin composition of the present invention produced by the above method is formed into a film or a sheet by extrusion, for example, or into a preform by injection molding, and then into a bottle by blow molding. Etc. Extrusion molding conditions at this time are within a range usually employed, for example, a cylinder temperature of 240 to 300 ° C., a screw rotation speed of 40 to 300 rpm, and a discharge pressure of 40 to 140 kg / c.
m ² , cooling drum temperature 5 to 40 ° C., etc. The injection molding conditions include a cylinder temperature of 270 to 300 ° C., a mold temperature of 5 to 40 ° C., a screw rotation speed of 40 to 300 rpm, and an injection pressure of 40 to 140 kg.
/ Cm ² or the like.

The polyethylene terephthalate resin composition according to the production method of the present invention can lower the crystallization temperature during molding. Specifically, the polyethylene terephthalate resin composition can be formed into a molded article by a differential scanning calorimeter. Warm crystallization temperature of 145 to 1
The temperature is preferably 70 ° C., particularly preferably 155 to 165 ° C. Here, the elevated crystallization temperature refers to the top temperature of the crystallization peak observed during the course of heating from room temperature to 285 ° C. at a rate of 20 ° C./min with a differential scanning calorimeter. .

Among the molded articles obtained by the above molding methods, the resin composition according to the present invention is used to form a bottle by a blow molding method such as a cold parison method in which a preform obtained by an injection molding method is biaxially stretched after reheating. Suitable for molding, for example, carbonated beverages, fruit juice beverages, alcoholic beverages, beverages such as tea and mineral water, soy sauce, sauces,
It is suitably used as a container for liquid seasonings such as mirin and dressings, edible oils, liquid detergents and cosmetics.

[0018]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist. Example 1 13.0 kg of terephthalic acid and 5.8 of ethylene glycol
2 kg of a slurry is prepared, and 0.30 kg of bis (2-hydroxyethyl) terephthalate is added in advance to prepare a slurry.
The mixture was sequentially supplied to the esterification tank maintained at a temperature of 50 ° C. over 4 hours. After completion of the supply, the esterification reaction was allowed to proceed for 1 hour, and then half of the mixture was transferred to a polycondensation tank, and phosphoric acid was added at 0.9%.
1 g and 0.92 g of germanium dioxide,
The temperature was gradually raised from 278 ° C. to 278 ° C., the pressure was gradually reduced from normal pressure, and the polycondensation reaction was carried out for 3 hours while maintaining the pressure at 0.5 mmHg. It was extracted in a strand shape, cooled with water, and cut with a cutter to obtain an elliptic cylindrical polymer chip. Subsequently, the obtained polymer chip is transferred by pneumatic transportation through a pneumatic transportation pipe to a stirring crystallization machine (Bepex), and the polymer chip surface is crystallized at 150 ° C.
The mixture was transferred to a stationary solid-state polymerization tower and dried at about 140 ° C. for 3 hours under a nitrogen flow of 20 liters / kg · hr.
Solid-state polymerization was performed for a period of time to produce a chip-shaped polyethylene terephthalate resin.

The obtained polyethylene terephthalate resin is coated with a low-density polyethylene ("UE320", manufactured by Nippon Polychem Co., Ltd.) on the entire inner wall surface to a thickness of 500 μm, and is a SUS shipping container (length 2 m, width 1.5).
m, height 2 m, loading capacity 5 tons) and transported by truck for about 5 hours. The polyethylene terephthalate resin composition after transport contained 5 ppb of low-density polyethylene and had an intrinsic viscosity of 0.74 dl / g.

The polyethylene terephthalate resin composition after transportation is dried in a vacuum dryer at 140 ° C. for 12 hours, and then subjected to an injection molding machine (“M-70A” manufactured by Meiki Seisakusho).
, Temperature of each part of cylinder and nozzle head 280
° C, screw rotation speed 200 rpm, injection time 60 seconds,
Each step-shaped plate-shaped plate having a thickness of 4 mm and 5 mm was injection-molded at a mold cooling water temperature of 10 ° C. For the obtained molded plate, measure the crystallization temperature of the resin composition, and transparency,
The results are shown in Table 1. In addition, the measuring method of each physical property is as follows.

Crystallization temperature differential scanning calorimeter (manufactured by Seiko Denshi Co., Ltd., “DSC220
C)), using a 5 mm thick portion of the molded plate, the temperature was raised from room temperature to 285 ° C. at a rate of 20 ° C./min, and the top temperature of the crystallization peak observed in the middle (heating crystallization) Temperature: TC ₁ ) was measured, and the temperature was further increased. When the temperature reached 285 ° C., the temperature was maintained for 3 minutes, and then the temperature was lowered at a rate of 10 ° C./min. (Cold crystallization temperature: TC ₂ ) was measured. Transparency haze meter (NDH-300A, manufactured by Nippon Denshoku)
, The haze was measured for portions having a thickness of 4 mm and 5 mm of the molded plate.

Comparative Example 1 In the same manner as in Example 1, except that the inner wall surface was filled and transported in a SUS transport container not coated with low-density polyethylene, each physical property was measured by injection molding. Also shown in Table 1.

[0023]

[Table 1]

[0024]

According to the present invention, it is possible to provide a method for producing a polyethylene terephthalate resin composition having an improved crystallization rate by lowering the crystallization temperature without lowering the transparency.

Claims (7)

[Claims] 1. A method for filling a granular material of polyethylene terephthalate resin in a transport container, the method comprising:
Or, at the time of discharge from the transport container, after contacting a member made of a crystalline thermoplastic resin different from the resin to contain a small amount of the crystalline thermoplastic resin, melt kneading and polyethylene terephthalate resin composition and What is claimed is: A method for producing a polyethylene terephthalate resin composition. 2. The method for producing a polyethylene terephthalate resin composition according to claim 1, wherein the member made of the crystalline thermoplastic resin is a pipe for filling polyethylene terephthalate resin granules. 3. The method for producing a polyethylene terephthalate resin composition according to claim 1, wherein the member made of a crystalline thermoplastic resin is a container for transporting polyethylene terephthalate resin granules. 4. The method for producing a polyethylene terephthalate resin composition according to claim 1, wherein the crystalline thermoplastic resin is a polyolefin resin. 5. The method for producing a polyethylene terephthalate resin composition according to claim 4, wherein the polyolefin resin is a polyethylene resin. 6. The method for producing a polyethylene terephthalate resin composition according to claim 4, wherein the polyolefin resin is a polypropylene resin. 7. The method for producing a polyethylene terephthalate resin composition according to claim 1, wherein the temperature-rise crystallization temperature of the resin composition formed into a molded body is in the range of 145 to 170 ° C.